I have fairly small skinny lips too and this is what I do to mine! I've never shared this so i'm not sure if it just works for me or whether its for everyone.. so try it out!
-Using petroleum jelly (vaseline), gently and thinly coat both lips until very shiny
-Wait until it has dried a little, then take a lipliner (I use Bourjois lip stain pen, but any will do) and line both your lips, following your natural shape or you could look like a clown!
-Before it dries, gently smudge the lipliner INWARDS, so it doesn't look like lipliner anymore, but a soft lipstick.
-Coat your lips again with vaseline, then dab at them gently with your finger or a tissue so they dont look too shiny.
-Finally, do an extreme pout so your lips go huge, and then slooowlyyyyyy go back to a normal look. This makes my lips stick out a bit
Ok well I hope that helped! Let me know if it works
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